Generally, in the commercial production of maleic anhydride by the catalytic oxidation of hydrocarbons, it is of ultimate importance to use catalysts which give high conversions of hydrocarbons to maleic anhydride.
Maleic anhydride is conventionally prepared by the oxidation of benzene; however, high percentages of converted benzene are lost in the form of carbon oxides. This process create unnecessary waste in that two carbon atoms are oxidized to useless waste.
The oxidation of 1,3-butadiene to produce maleic anhydride eliminates this waste. This process has been conducted before in the art using various catalysts, for example West German Pat. No. 1099111 discloses the preparation of maleic anhydride by the catalytic vapor phase oxidation of 4-carbon hydrocarbons in the presence of catalysts of the composition AO.sub.3 --B.sub.2 O.sub.5 --M.sub.2 O.sub.5 --N.sub.x O--R.sub.2 O (in which A is Cr, Mo, W, or U; B is V or Nb; M is P, As, Sb or Bi; N is Cu, Ag, Fe, Co or Ni; R is Li, Na, K, Cs or Rb; x is 1- 2). U.S. Pat. No. 3,907,834 discloses the preparation of maleic anhydride from n-butylenes, 1,3-butadiene, crotonaldehyde and furan in the presence of a catalyst containing antimony, molybdenum, and a reducing agent selected from the group consisting of molybdenum, tungsten, magnesium, aluminum and nickel. British Pat. No. 1,157,117 discloses the production of maleic anhydride from a saturated aliphatic hydrocarbon having 4 carbon atoms in the molecule or an unsaturated aliphatic hydrocarbon having 4 or 5 atoms in the molecule in the presence of a catalyst comprising an oxide of molybdenum and at least one other oxide if tin, antimony, titanium, iron or tungsten.
The primary object of the present invention is to provide a process for producing maleic anhydride using novel catalysts with improved yields of maleic anhydride and decreased waste byproducts.
It is a further object of this invention to provide a method for making the novel and improved catalyst of the character indicated.